While driving to work lately, I've been noticing yellow wildflowers growing in the empty space on Richmond Road across from the Bayshore shopping mall. This is the area that had hosted construction workers and their equipment for so long due to the building of the new transitway lane that extends from Pinecrest to Bayshore. The machines and the workers are all gone now, and taking over their place are these brilliant yellow flowers. I'd only begun noticing them toward the end of November, and each morning I'd survey the field to see if they'd wilted with the frost. As they continued to bloom despite the cold nights and hard frosts, my curiosity grew. I began to wonder how I could photograph them in order to identify them.

Wild Mustard

Last week I had to take the bus to work from Kanata, and noticed a lot of these yellow flowers growing in the ditch and the field behind the new Pinecrest bus shelter. This is an area that is easily accessible, and so on Wednesday at lunch I took the bus to the new Pinecrest station and began photographing these bright flowers still blossoming in December.

Wild Mustard on December 2, 2009

Once I got home and studied my photos, I was able to identify the plant as Wild Mustard [Sinapis arvensis L., Brassica kaber (DC.)]. This is an aggressive weed which is native to Europe, Asia and North Africa, and has now become common in Ontario. Found in cultivated fields, gardens, pastures, river banks, roadsides and waste places, it is an annual plant that reproduces only by seed and whose flowers can bloom from late spring to early fall for 1-2 months. Given the unseasonably warm, sunny November we have had, perhaps it is not surprising that this plant continues to flourish in these recently disturbed areas. Seeds that are buried deep can remain viable in the soil for up to 60 years, and germinate later once the ground is cultivated and the seeds are brought to the surface.

Wild Mustard Blossoms

Although the carpet of yellow flowers looks beautiful, Wild Mustard is very invasive and aggressive. It is also an alternative host for a number of pests including insects, nematodes, fungi, viruses and bacteria that cause damage to cultivated crops.

However, this plant does have some beneficial aspects. The flowers are a prime source of pollen and nectar, attracting pollinating insects such as small bees and flies as well as small white butterflies, namely the Cabbage White and Checkered White butterflies. In addition, the caterpillars of the Cabbage White and the Checkered White may feed on the foliage.

Wild Mustard

I was just thrilled to see these splashes of colour against the still-green grass given the late date. With the warm weather, green grass, and flowers blooming it still seems like early fall rather than the beginning of the winter season. Hopefuuly spring will arrive on time and make for a short winter!